Predicting the Intensity for Performing Supramaximal Incline Treadmill Interval Training in Distance Runners

Ferley, DD and Vukovich, MD. Predicting the intensity for performing supramaximal incline treadmill interval training in distance runners. J Strength Cond Res 33(5): 1354-1361, 2019-Recent evidence highlights the effectiveness of 30-second bouts paired with level-grade supramaximal interval training (SMIT) and incline treadmill training (INC), respectively, in distance runners. Although INC has been described as a form of SMIT, no investigation of INC involving a supramaximal intensity and 30-second bouts has occurred; hence, no established recommendation for prescribing a supramaximal intensity with 30-second bouts for INC exists. Therefore, the purpose of this investigation included reporting on the time-to-exhaustion (Tmax) response and test-retest reliability of running on a 5% grade using supramaximal intensities of 110, 115, 120, 125, and 130% of the velocity associated with maximum oxygen consumption (Vmax). Additionally, these measures were assessed during 140% Vmax and 1% grade. A second aim included determining the %Vmax associated with a 30-second effort via bivariate analysis. Twelve distance runners (age, 26.9 ± 4.8 years; body mass, 69.2 ± 11.7 kg; height, 177.3 ± 10.2 cm; and V[Combining Dot Above]O2max, 61.4 ± 6.3 ml·kg·min) completed 2 Tmax trials at each intensity for measures of reliability. The dependent variable was the Tmax of each condition. Statistical significance was set to p ≤ 0.05. Student's t-test revealed no significant differences between trials for all intensities. One-way analysis of variance revealed (a) that Tmax during INC at 110% Vmax was significantly different than all conditions except 115% Vmax and (b) no significant difference in Tmax between 120, 125, 130, and 140% Vmax conditions. In conclusion, Tmax of all conditions proved reliable, and bivariate analysis revealed running at 125% Vmax on a 5% grade yielded a 30-second effort.